What is a back cross?

A back cross refers specifically to the breeding of an F1 individual (the first filial generation, which typically results from a cross between two true-breeding parents) with one of its parent strains. This practice is significant in genetics as it allows the study of the inheritance of traits and the identification of homozygous and heterozygous offspring. By crossing the F1 with a parent, researchers can assess the expression of particular traits and analyze how these traits are passed down through generations, thus providing insight into domestic breeding strategies or the development of specific phenotypes in plants or animals.

The other options describe different genetic crosses or concepts. For instance, a cross between two F1 individuals involves the second filial generation (F2), which depends on the combinations of alleles inherited from both parents. A genetic cross involving multiple gene traits refers to polygenic inheritance, where several genes affect a single trait rather than focusing on the back cross specifically. Lastly, a cross resulting in homozygous offspring is a broader idea that can arise from various types of genetic crosses but is not limited to the definition of a back cross. Each of these scenarios has its own significance, but the focus of a back cross is distinct and centers around the relationship between the F1